#include<unistd.h>
#include<stdlib.h>
#include<stdio.h>
#include<string.h>

#include <sys/mman.h>
#include <sys/stat.h>        /* For mode constants */
#include <fcntl.h>           /* For O_* constants */

#include "shm_com.h"

int main(void)
{
    int running = 1;
    void* shared_memory = NULL;
    struct shared_use_st* shared_stuff;
    char buffer[BUFSIZ];

    int fd = shm_open(SHM_FILE_NAME, O_RDWR, 0666);
    if (-1 == fd)
    {
        perror("shm_open failed\n");
        exit(EXIT_FAILURE);
    }

    shared_memory = mmap(NULL, SHM_BUF_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (MAP_FAILED == shared_memory)
    {
        perror("mmap failed\n");
        exit(EXIT_FAILURE);
    }
    printf("memory attached at %p\n", shared_memory);

    shared_stuff = (struct shared_use_st*)shared_memory;
    shared_stuff->written_by_you = 0;
    while(running)
    {
        while (1 == shared_stuff->written_by_you)
        {
            sleep(1);
            printf("waiting for client...\n");
        }

        printf("Enter some text: ");
        fgets(buffer, BUFSIZ, stdin);

        strncpy(shared_stuff->some_text, buffer, TEXT_SZ);
        shared_stuff->written_by_you = 1;

        if (strncmp(buffer, "end", 3) == 0)
        {
            running = 0;
        }
    }

    if (-1 == munmap(shared_memory, SHM_BUF_SIZE))
    {
        perror("munmap failed\n");
        exit(EXIT_FAILURE);
    }

    return 0;
}
